In this paper, an analytical approach is used for assembly line rebalancing and worker assignment for single and mixed-model assembly lines based on a heuristic-simulation algorithm. This approach helps to managers to select a better marketing strategy when different combinations of demands are suitable.Furthermore, they can use it as a guideline to know which worker assignment is better for each combination. We show the efficiency of the proposed approach for single and mixed-model assembly lines using different benchmarked standard test problems with different number of tasks, stations, skilled workers and demands. Comparisons show the heuristic-simulation algorithm is faster than the GAMS software, and its results are optimum or very close to the optimum values.